If a shirt costs $40 after a 20% discount, what was the original price? A. $45 B. $50 C. $60 D. $55

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We have a discount problem. A shirt costs 40 dollars after a 20 percent discount. We need to find the original price. Let's call the original price P. Let's understand what a 20 percent discount means. If the original price is P, then a 20 percent discount means the customer pays 100 percent minus 20 percent, which equals 80 percent of the original price. So the discounted price of 40 dollars represents 80 percent of the original price P. Now let's set up the equation. The discounted price of 40 dollars equals 0.80 times the original price P. To solve for P, we divide both sides by 0.80. This gives us P equals 40 divided by 0.80, which equals 50 dollars. Let's verify our answer. If the original price was 50 dollars, then a 20 percent discount would be 50 times 0.20, which equals 10 dollars. The final price would be 50 minus 10, which equals 40 dollars. This matches the given information, so our answer is correct. The answer is B, 50 dollars. To summarize what we learned: When solving discount problems, first identify what percentage the customer actually pays. Set up an equation where the discounted price equals that percentage times the original price. Solve by dividing the discounted price by the percentage. Always verify your answer by checking the calculation works both ways.